Rubber sole



B. B. CRAVER June 20, 1939.

RUBBER SOLE Original Filed June 13, 1936 ATTORNEY Patented June 20, 1939 UNITED STATES RUBBER SOLE Bates B. Graver, Waterbury, 0onn., assignor, by mesne assignments, to United States Rubber Company, New York, N. Y., a corporation of New Jersey Original application June 13, 1936, Serial No.

85,072. Divided and this application August 26, 1937, Serial No. 161,007

1 Claim.

This application is a division of application Serial No. 85,072 filed "June 13, 1936.

My invention relates to rubber soles and the combination of rubber soles and heels, and more particularly to the improvements of the antislipping or anti-skidding characteristics thereof by the provision of small slits in the ground engaging surfaces thereof.

It is wellknown that footwear having rubber heels and/or soles may become very slippery when used on wet pavements, walks, or boardwalks, particularly if the weight of the wearer-is placed on a wet metal part.

I have found that the anti-slipping or anti-' skidding characteristics of rubber soles and the combination of rubber soles and heels may be materially improved by providing a number of slits in the exposed rubber surface. Such slits may vary from a thin slit such as is formed by a knife cut without-substantial removal of material to a narrow slot such as is formed by a thin saw and in which some material is removed but which is still sufficiently narrow so that the side walls engage to mutually support each other when load is applied. The presence of the thinv edges of, the slits provides additional traction. surface, as compared with a smooth rubber surface, and also the slits provide small passageways through which the liquid or liquid film may be squeezed to permit the rubber surface to have a relatively dry contact with the underlying road or walk surface. The slits may besuperimposed on various designs of sole and heel configurations or they may be applied directly to otherwise smooth rubber surfaces.

The accompanying drawing illustrates certain present preferred embodiments of the invention, in which:

Fig. 1 is a perspective view of a combined heel and sole embodying my invention;

Fig. 2 is a plan view of a modified form of the heel and sole;

Figs. 3, 4, 5 and 6 are similar views of further modifications of the invention Fig. 7 is a similar view of a sole embodying my invention.

Referring particularly to Fig. 1, a wear resisting surface for a footwear article is illustrated in the form of a combined heel and sole I in which the ball portion 2 of the sole and the tread sur-' face 3 of the heel are interrupted by a considerable number of small slits or incisions 5 for improving the traction qualities of the shoe to which it is attached. These incisions extend transversely entirely across the ground engaging surfaces of the sole and heel. The transversely arranged incisions are particularly adapted to prevent back slipping of the shoe. Incisions 5 are preferably made after the footwear is vulcanized by a cutting operation, such as by a sharp knife or very thin saw which removes substantially no material. The term incision as used herein means a cut formed in the surface of the Vulcanized rubber composition without the removal of substantially any material, with the result that the opposite walls 'of the incision normally engage one another. Incislons which are wider than inch remove so much of the wearing surface of the rubber'that the loss of the wearing surface is not compensated for by the increased traction effect. The spacing of the'incisions depends somewhat upon the thickness of the rubber .to which it is applied, although a spacing range of from A; inch to 1 inch is contemplated. In general, the thinner the stock, the shallower and closer the incisions. A convenient depth for the initial incisions is one-third of the thickness of ,the stock, although the use of incisions on stock which is less than .2 inch is not recommended. For heavy service boots, such as hunts ing boots, miners boots, and the like, having,

As shown in Fig.2, in the event it is desired tohave a smooth appearing outer edge of the soles and/or heels, uncut margins 6 and I of the order of inch in width may be provided aroundthe edges of the sole and heel portions. respectively. 40

Referring to Fig. 3, a combined sole and heel 8 is shown provided with longitudinal incisions 9 which are particularly useful in preventing side slipping. In Fig. 4, incisions ID are shown set at an angle at approximately 45 degrees to the longitudinal center of the sole and heel ll. Such incisions combine certain of the advantages of the transverse incisions in preventing back slipping and certain of the advantages of the longitudinal incisions in preventing side slipping of the shoe. In Fig 5 a double diagonal arrange-. ment of incisions l2 and l3 is illustrated. The intersections of the incisions l2 and I3 break the wearing surface up into a plurality of square blocks which are flexible relative to each other so that they move slightly while maintaining their grip on the ground surface thereby reducing scuffing to a greater degree than do the arrange-- ments shown in the previously described figures. 5 Referring to Fig. '6 there is shown a combined sole and heel I in which longitudinally extending grooves ii are originally molded. If desired the grooves l5 may extend through the margin of the surface of the tread of the sole and heel w portions. Transverse incisions i6 intersect the grooves l5 so that relatively short pads are pro- ,vided for the squeezing out the liquid film from between the rubber surface and the pavement. Such adesign of the combinedsole and heel is 15 particularly useful for, very heavy service boots such as hunting and miners boots." I

Fig. '7 illustrates a sole l| having transverse incisions l8. By applying the incisions to heels the jar experienced with walking is'niaterially reduced as the'subsections of the wearing surface are free to adjust themselves to the inequalities of the worn heel or ground surface and/or load so that a more uniform overall pressure is obtained than :5 is usually obtained where a less flexible body of rubber is employed for the heel.

While I have. illustrated and described several designs or patterns of incisions,- it will be understood that other patterns may be used within io'the spirit of the invention and with equally good results. The several modifications of the invention are all characterized by the application of incisions, either so narrow as to be substantially invisible, or so that the opposite walls normally a engage, which result in squeezing of a liquid film from between the rubber surface and the ground thereby insuring a better contact between the rubber surface and the ground surface. Such constructions are particularly useful where the 0' footwear is used wet and slimy places. The application of the invention to heels also reduces the jarring. By reason of the subdivision of the wearing surface into small units, these units are free to flex slightly and accommodate themselves to unevennesses in the ground surface or inequalities of the imposed load without slipping or scuffing thereby giving the footwear better wearing characteristics. The various patterns of incisions may be made in a sole and/or heel having a smooth or uneven surface, evamples of the latter are the grooves ii in Fig. 6, or they may be made in surfaces having various designs.

While I have shown and described present preferred embodiments of my invention, it is to be understood that the invention may otherwise be.

extending inwardly but partially to leave an un-' cut base integral with the sections, and said slits being of such a spacing and depth as to enable the tread sections to flex on the uncut base of the outsole to an extent to tilt up and expose the corners of the sections between the tread surfaces of the sections and the walls of the slits when the foot wearing the shoe and applying weight on the tread surface tends to slip upon some desired supporting surface with which the tread surface is in contact.

I BATES B. CRAVm. 

